Function ColNamesInSelect

pkg/walk/walker.go:255–284

ColNamesInSelect finds all referred variables in a Select Statement. (variables = sub-expressions, placeholders, indexed vars, etc.) Implementation limits: 1. Table with AS is not normalized. 2. Columns referred from outer query are not translated.

(sql string)

//	1. Table with AS is not normalized.
//  2. Columns referred from outer query are not translated.
func ColNamesInSelect(sql string) (referredCols ReferredCols, err error) {
	referredCols = make(ReferredCols, 0)

	w := &AstWalker{
		Fn: func(ctx interface{}, node interface{}) (stop bool) {
			rCols := ctx.(ReferredCols)
			if isColumn(node) {
				nodeName := fmt.Sprint(node)
				// just drop the "table." part
				tableCols := strings.Split(nodeName, ".")
				colName := tableCols[len(tableCols)-1]
				rCols[colName] = 1
			}
			return false
		},
	}
	stmts, err := parser.Parse(sql)
	if err != nil {
		return
	}

	_, err = w.Walk(stmts, referredCols)
	if err != nil {
		return
	}
	for _, col := range w.UnknownNodes {
		log.Printf("unhandled column type %T", col)
	}
	return
}

func AllColsContained(set ReferredCols, cols []string) bool {
	if cols == nil {